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Biomedical subjects

S Kneist

Publications and source records attributed to S Kneist.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Microbial colonization of carious progression stages in the dentin of human teeth--a controlled therapeutic study].

In a controlled clinical trial the microflora of the cavity floor of 70 primary lower second molars with deep carious lesions were determined after caries excavation. The teeth were extracted and pulpal status was evaluated after 16 months of microbial control to determine the etiopathogenic role of germs for carious progression in dentine. 67% of the primary molars were free from pulpal inflammations. Soft carious dentine were significantly higher infected than the clinically acceptable hard dentine. Only in 40% of the cavity floors the microorganisms were eliminated. In the infected teeth basophilic microorganisms were found in causality to pulps without inflammations; acidogenic streptococci and lactobacilli were involved in pulpal inflammations. Results indicate that the latter genera of microorganisms are of etiological significance for carious progression in dentine.

Actinomycetales↗
PubMed1987

[Microflora in a controlled caries model study in rats].

Changes of dental plaque were investigated in Osborne-Mendel-rats under the influence of a sucrose-containing diet as well as the inhibition of it by antibiotics (streptomycin, erythromycin, penicillin) in order to find out the optimal conditions of animal association with Str. mutans (OMZ 176). The cariogenic diet did not alter the isolated total germ numbers, but modified the flora to a streptococcal one. The application of an erythromycin/penicillin mixture caused a 100 fold decrease of the germ number and streptococcal elimination so that an association of the germ Str. mutans detectable by microbiological methods could take place at this moment. The obtained caries scores differed from the non-contaminated group. Mono-associated gnotobiotic Wistar rats developed more carious lesions than conventional animals of the same strain; therefore Str. mutans OMZ 176 was classified as high cariogenic.

Animals↗
PubMed1983

Genotoxicity of Fusarium mycotoxins (nivalenol, fusarenon-X, T-2 toxin, and zearalenone) in Chinese hamster V79-E cells in vitro.

The mycotoxins nivalenol, fusarenon-X, T-2 toxin and zearalenone were checked for clastogenic damage, induction of SCEs and cell cycle delay in Chinese hamster V79-E cells in vitro. The trichothecenes nivalenol, fusarenon-X and T-2 toxin provoked a marked toxicity as especially expressed by cell cycle delay. As compared to toxicity, they are weak clastogens. Addition of S9 mix toxified nivalenol, detoxified T-2 toxin and had no marked influence on fusarenon-X activity. SCE values were slightly increased. It is suggested that the effects observed are unspecific and are caused by inhibition of protein synthesis. Zearalenone was inactive in the three assays. Problems of genotoxicity and carcinogenicity of Fusarium toxins are discussed.

Animals↗
PubMed1982

Patulin, a further clastogenic mycotoxin, is negative in the SCE assay in Chinese hamster V79-E cells in vitro.

Patulin is a potent inducer of chromatid-type aberrations in Chinese hamster V79-E cells, but loses its activity when 9000 g supernatant of rat-liver homogenate is added. The narrow dose range of patulin clastogenicity shows a quantitative relationship between absolute amount of mycotoxin applied and the number of indicator cells treated. Within a dose range permitting survival of V79-E, patulin does not induce an increase of the SCE rate. It is suggested that patulin clastogenicity is caused by interaction with chromosomal proteins and that DNA is not the virtual target of this mycotoxin.

Animals↗